As explained for example in the paper “The Untapped Potential of Trusted Execution Environments on Mobile Devices” by J.-E. Ekberg, K. Kostiainen and N. Asokan in IEEE Security & Privacy, volume PP edition 99, 16 Apr. 2014, it is known to make the functioning of electronic devices secure by using a trusted operating system that makes it possible to provide a trusted execution environment (TEE) in which only certain applications can be installed and executed.
Such a trusted environment is generally offered alongside a rich execution environment (REE) in which the security constraints are looser and a greater number of applications can therefore be installed. The rich environment relies on the electronic device executing a rich operating system (Rich OS) distinct from the trusted operating system.
In order to guarantee good isolation between the two execution environments and therefore good functioning security, dedicated memory spaces are generally provided for each execution environment, notably in random access memory.
It has nevertheless been proposed additionally to use a shared memory area accessible by the two execution environments, as mentioned in particular in the presentation “Next Generation Mobile Rootkits” by T. Roth, BlackHat Europe 2013 (cited as reference [15] in the paper referred to above).